Granted Patent B2

US 7,590,087 · App. 11/080,526 · Granted Sep 15, 2009

Abstract

Claims (16)

1. A method for wireless data transmission between a base station and one or more transponders, the method comprising the steps of:

emitting electromagnetic carrier waves by the base station; and

transmitting symbols from at least one of the transponders by modulation and backscattering of the electromagnetic carrier waves,

wherein a change in a modulation state takes place substantially synchronously with synchronization markers transmitted by the base station, and

wherein a change in the modulation state is performed by the at least one transponder with a predetermined time delay relative to the synchronization markers.

2. The method according to claim 1 , wherein the time delay is specified such that it lies in a range from one eighth to one quarter of a duration within which a symbol is coded.

3. The method according to claim 1 , wherein the time delay is specified by the base station in that it transmits a reference marker in a header section of a data packet.

4. The method according to claim 2 , wherein the symbols are coded using NRZ (non return to zero) or NRZI (non return to zero inverted) coding,

5. The method according to claim 1 , wherein the synchronization markers are generated by double sideband modulation having a suppressed carrier,

6. The method according to claim 1 , wherein the transponders are passive transponders.

7. The method according to claim 1 , wherein the symbols that are transmitted from at least one of the transponders are transmitted to the base station, a different base station, or a different transponder.

8. A method of transmitting data from a transponder to a base station, the method comprising:

receiving a modulation signal, which is transmitted from a base station, by the transponder;

generating, by the transponder, a synchronization marker signal on the basis of the received modulation signal;

transmitting data from the transponder by backscattering the modulation signal on the basis of the synchronization marker signal, wherein the backscattered modulation signal is transmitted after a predetermined time delay in a change of state of the synchronization marker signal.

9. The method according to claim 8 , wherein the data is transmitted from the transponder to the base station that transmitted the modulation signal, to a different base station, or to a different transponder.

Assignments (19)